Trigger finger

What is trigger finger?

Trigger finger is a condition where a finger or thumb clicks, catches or locks in a bent position as you try to straighten it. It happens when a tendon that bends your finger becomes thickened and can no longer glide smoothly through its tunnel.

What are the symptoms of trigger finger?

Symptoms usually build up gradually and tend to be worse first thing in the morning. You may notice:

• a small, tender lump (nodule) in your palm, at the base of the affected finger or thumb
• pain when you bend or straighten the finger, or when you press on the lump
• a clicking or popping feeling as the finger moves
• stiffness, especially in trigger thumb
• your finger locking in a bent position, sometimes needing your other hand to straighten it.

It can affect more than one finger, and sometimes both hands. Symptoms often ease once you've been using your hand for a while.

What causes trigger finger, and who is at risk?

Trigger finger happens when the tendon that bends your finger, or the tunnel (sheath) it runs through, becomes swollen and thickened. This roughens the tendon's surface, so it catches rather than gliding smoothly, particularly at the entrance to the tunnel.

It's not always clear what causes this, but you may be more likely to get trigger finger if you:

• are over 40
• have diabetes, especially insulin-dependent diabetes
• have rheumatoid arthritis
• have had an injury to your hand, such as a knock.

There's little evidence that it's caused by work activities, though using your hands at work, at home, in the garden or during sport can make the pain worse. It's not caused by osteoarthritis.

Are there different types of trigger finger?

Trigger finger can affect any finger, and when it affects the thumb, it's called trigger thumb. It's possible to have it in more than one digit at a time, and it can affect both hands.

The main difference with trigger thumb is that it particularly reduces movement at the thumb's end joint, while the other symptoms are similar to trigger finger in the other digits.

How is trigger finger diagnosed?

A doctor or hand therapist will usually diagnose trigger finger by examining your hand and asking about your symptoms. They'll check the movement in your finger, feel for the tender lump in your palm, and see if pressing or moving the finger brings on your symptoms.

Special tests aren't usually needed, but occasionally further examination is used to rule out other conditions that can cause similar symptoms.

How is trigger finger treated?

Trigger finger is not harmful, but it can be a painful nuisance. Some mild cases improve over a few weeks without any treatment.

Non-surgical treatment

• avoiding or changing activities that bring on your symptoms, where possible
• exercises to keep your finger moving and prevent stiffness, done four to five times a day
• a splint worn at night to hold your finger straight, which can be custom-made by a hand therapist, or even a simple splint made from a lollipop stick and tape
• over-the-counter painkillers, such as paracetamol or ibuprofen, or anti-inflammatory gels
• a steroid injection into the finger or thumb, which relieves pain and triggering in around 70% of cases. Improvement can take from a few days to several weeks, and a second injection is sometimes tried

With advice and exercises, symptoms often improve within 12 weeks, though this varies from person to person.

Surgical treatment

If other treatments haven't worked, you may be offered:

• A percutaneous release, where a surgeon uses a needle under local anaesthetic to release the tight part of the tunnel; this isn't suitable for every case.
• Surgical release, a small operation under local, regional or general anaesthetic, where the surgeon widens the tunnel through a small cut in your palm.

After surgery, you'll usually need a small dressing for 10 to 14 days, but you can use your hand lightly from the day of the operation, and moving your finger helps your recovery. Pain relief is usually quick, and it's uncommon for the triggering to come back.

When should I see a doctor?

See a GP if you think you have trigger finger and your symptoms don't improve, or if they're stopping you doing your usual daily activities.

If you're using a splint, contact your hand therapist promptly if it's rubbing, uncomfortable, or causing skin irritation.